Process for removing dust and condensable vapors from gases



June 15, 1954 L. D. ETHERINGTON 2,681,125

PROCESS FOR REMOVING IIDUST AND CONDENSIBLE VAPORS FROM GASES 2 Sheets-Sheet l Filed Aug. 30, 1952 msu L M 7 u B W ngon n've ntor Juil? 15,1954 L. D. yE'rl-lrslilnlcn-ON 2,581,125

PRocEss FoRREMov'ING DUST AND coNDENsIBLE vAPoRs FROM GASES Filed'Aug. 30, 1952 l72 Sheets-Sheet 2 C2 FRACTION 8| /80 c3 FRAcwrloN4 25 I LEWIS D. ETHERINGTQN INVENTOR BY f..,e-@ ATTORNEY Patented June 15, 1954 UNITED STATES PROCESS FOR REMGVING DUST AND CON- DENSABLE VAPGRS FRUM GASES Lewis l). Etherington, Cranford, N. J., assigner to Standard Oil Development Company, a corporation of Delaware Application August 30, i952, Serial No. 307,300

9 Claims. 1

This invention concerns a method for recovering entrained solids and removing condensible vapor from at least two gas streams containing the same solid and condensible vapor. More particularly, it relates to a mehod for removing entrained solids from and dehumidifying two or more product gas streams produced when separating a mixture of gasiform hydrocarbons into various fractions by passing the mixture through a moving or iluidiaed bed of nely divided adsorbent. It has particular application to fractional adsorption processes in which the adsorbent is activated carbon and is present in the form of a uidized bed of nely divided particles, and stripping steam is used to desorb products from the activated carbon.

It is well known to fractionate a mixture of gasiform hydrocarbons by contacting the mixture with an adsorbent such as activated carbon. This adsorbent has the property of selectively adsorbing hydrocarbons according to their molecular weights or chemical types. For example, where all of the components of a hydrocarbon mixture are of the same chemical type, activated carbon will adscrb a high molecular weight hydrocarbon in preference to a low molecular weight one. It is this property of activated carbon and other similar adsorbents that has been uptilized in fractionating gasiform hydrocarbon mixtures and in particular those mixtures of hydrocarbon gases that are not condensible at ordinary temperatures and pressures.

A. brief description of a conventional process and apparatus for fractionally adsorbing a hydrocarbon gas mixture will be of assistance in pointing out the objects and advantages of the present invention. For the purpose of the ensuing description, it will be assumed that it is desired to fractionate a mixture of C1, C2, and C3 hydrocarbons into individual C1, C2, and Ca fractions. Mixtures such as this are commonplace in the petroleum industry where they are derived from a variety of producing and rening processes. The C1 fraction includes methane and lighter gases; the C2 fraction consists primarily of ethane and ethylene; and the Cs fraction includes propane, propylene and small amounts of lighter and heavier boiling hydrocarbons. A typical renery Ci-Cz-Ca stream will contain about to 15 volume per cent of C3, 10 to 30 volume per cent of C2, and the remainder methane and lighter boiling gases. It will be noted that hydrocarbon feed stocks other than this particular one, and operating conditions other than those to be stated can be employed without departing from the spirit of the present invention.

A conventional adsorptive fractionation process may be best described by referring to Figure l of the two figures that accompany this description.

Figure l illustrates a conventional adsorptive fractionation system which has incorporated within it a recovery system that constitutes a preferred embodiment of the present invention.

Figure 2 illustrates an alternative recovery system which constitutes another embodiment ci the present invention.

Referring to Figure 1, a feed gas composed substantially of C1, C2, and C3 hydrocarbons, ows through line It into tower Il at an intermediate point. Tower II contains a dehydration zone 9, and adsorption section I2 containing a cooling zone I5, a rectification section i3, and a heating and stripping section I4. The adsorption section i2 is that portion of tower ii that is disposed between the feed point and the top of the tower. This section effects the adsorption of the intermediate and heavier constituents from the feed gas.

Rectification section I3 lies immediately below l the entry point of the feed gas, and it is in this section that less adsorbable constituents are stripped from more adsorbable constituents by upward moving reflux vapors.

Heating and stripping section I4 is positioned between rectication section I3 and the bottom of the tower. In this section of the tower, the most strongly adsorbed constituents of the feed are stripped from the adsorbent by means of a stripping medium such as steam introduced through line i@ in conjunction with heat supplied by heating means It.

The feed gas, as it enters tower I contacts a moving fluidized bed of `activated carbon, which flows from the top of the tower toward the bottom of the tower. The carbon employed is in nnely divided form and conventionally has a particle size distribution about as follows:

Table 1 Particle Size in Microns The preferred particle size characteristics of any given adsorbent may vary materially from the above values. It is well known in the art of luidizing solids that different materials require different particle size distributions for best fluidity'.

As the feed gas rises through adsorption section l2, the C2 and C3 fractions being more adsorbable than the C1 fraction are removed from the gas stream. The C1 fraction continues to rise through tower ll and eventually is withdrawn from the tower through overhead line B.

The fluidized bed of activated carbon containing the C2 and C3 hydrocarbons moves downwardly from adsorption section l2 to rectication section !3 and thence to heating and stripping section itl. In the upper part of section E3, refluxing C2 vapors selectively desorb C1 hydrocarbons from the carbon. in the lower part the reuxing C3 vapors similarly desorb C2 hydrocarbons which are then withdrawn from rectification section i3 at an intermediate point through line 2|. inasmuch as this side stream C2 fraction generally contains unavoidable equilibrium amounts of C3 and heavier hydrocarbons, it is passed to a secondary fractional adsorption tower 22 for further rectication. A stream containing substantially pure C2' hydrocarbons is removed from secondary tower 22 through overhead line 23.

Fluidized carbon passing downwardly through secondary tower 22 is withdrawn from the bottom of this tower through line 2li and ilows back to the main adsorption tower H.

The fluidized activated carbon bed in tower l l, meanwhile, continues to now downwardly from rectification section i3 to heating and stripping section lli, wherein the C3 hydrocarbons are removed from the carbon by combined heating and stripping means.

A stream containing substantially pure C3 hydrocarbons plus the bulk of the stripping steam is withdrawn from the top of the heating and stripping section through line 25. This section of tower l I is generally operated at temperatures of about 500 F.

The stripped carbon is withdrawn from the bottom of tower Il through line i8 and a rst portion of it is then recycled through line il to the top of tower il. The second portion of the stripped carbon is recycled through line 26 to the top of tower 22.

Since the stripped carbon is at a temperature of about 500 F., it must be cooled before it can regain its ability to adsorb hydrocarbons. A ccnventicnal method for achieving such cooling consists in locating suitable cooling means 2l in the upper part of tower l! and cooling means 8 in the upper part of tower 22.

It will be noted also that the carbon as it leaves the bottom of tower Ii contains an appreciable amount of adsorbed water vapor. To provide maximum carbon activity for the hydrocarbon separations, it is necessary that this adsorbed water vapor be removed. This objective is conventionally achieved in the topmost portion of tower il, designated as the dehydration zone 8, where the rising C1 hydrocarbons serve to strip the water vapor from the carbon. The carbon feed to tower 22 is similarly stripped oi" water by the Cz product and cooled in the upper portion of tower 22. rBhe bulk of the stripping steam appears in the C3 product leaving tower l l through line 25. The C1 stream in line 20, the C2 stream in line 23, and the C3 stream in line 25 all contain relatively large amounts of wat-er vapor and also substantial amounts of entrained particles of activated carbon. For example, a typical C1 stream may contain from about 5 to 30 volume per cent of steam; a C2 stream about 5 to 15 volume per cent of steam; and a C3 stream about 50 to 90 volume per cent of steam. The water vapor and carbon containedin these'streams must be separated from them in order to obtain the hydrocarbon fractions in relatively pure form. it is eminently desirable that the entrained carbon be Vrecovered in a form that is suitable for immediate reintroduction within tower Il. Cyclone separators are conventionally employed to remove a large amount of the carbon in the streams, but additional methods must be employed to recover greater than 99.9% of the carbon as is required by the overall process. Depending upon the number of cyclones employed to make a preliminary separation and also upon the height of the drawoil point above the carbon bed, the various gas streams may contain as little as .l pound of carbon per 1000 cubic feet of gas; but they will usually contain about 1 to 2 pounds of carbon per 1G00 cubic feet of gas.

A number of methods have been suggested or employed in conjunction with cyclone separators for recovering the required amount of carbon and water vapor from the hydrocarbon streams described above. A particularly desirable method is one wherein a gas stream contairnng a nonoondensing gas, a condensible vapor, and iinely divided solids is first passed to conventional equipment such as cyclones which remove the bulk of the entrained solid but, 'unfortunately which are inadequate to eiect the ultimate high recovery desired. The gas from the cyclones is then passed to a tower which is comprised of a scrubbing Asection and a condensation section. The feed gas in this instance is introduced to the bottom of the scrubbing section, where it is initially contacted with a recirculated slurry whose temperature and flow rate are controlled so as to remove all of the solids and a predetermined portion of the condensible vapors from the feed gas. Just enough oi the vapors are condensed in the scrubbing section to provide the desired concentration of solids in the slurry resulting from the condensed vapors and the precipitated solids. This method has been described at length in pending patent application S. N. 307,270 led by R. S. Wood on August 30, 1952.

The scrubbed and partially dehurnidiried `feed gas from the lower scrubbing section then enters the dehumidication section wherein additional vapors are condensed from the gas in the substantial absence of any solids. The scrubbed and dehumidied non-condensing gas fraction is withdrawn from the top of the dehumidificaticn section. Meanwhile, the vapors condensed in this section are separately collected and withdrawn from the bottom of this tower section for any further desired use.

An object of the present invention is to utilize the apparatus and method described above in a novel manner for the purpose of processing hydrocarbon gas streams such as the C1, C2, and C3 product streams from an activated carbon iractional adsorption unit of a type described earlier in this specication. More particularly, it is an object of the present invention to integrate the scrubbing and dehumidication operations performed on a plurality of such streams so as to (1) recover at least 99.9% of the carbon lcontained in all of the gas streams as a single, pumpable carbon-water slurry of a character that can be directly reintroduced to the primary adsorption tower; (2) recover substantially all of the steam or water vapor as condensed water (except that water present in slurry form) in the form of a single stream; (3) separately recover the scrubbed and dehumidied C1, C2, and C3 fractions; (4) avoid contamination of the various products with any extraneous materials; and (5) employ separate scrubbing zones for each of the gas streams but only one common condensation zone. They advantages of integrated operations in treating at least two separate feed gas streams will be apparent from the following discussion.

The present invention achieves its objects by making use of the act that the bottoms fraction from a conventional activated carbon adsorption tower contains appreciably more water vapor than does the overhead fraction or any or the side stream fractions. For example, in the particular process partially described earlier in this specification and illustrated in attached Figure 1, the C1 and C2 fractions will contain less water vapor than the C3 fraction. Furthermore, the total steam quantity in both the C1 and C2 fractions is usually more or less of the order desired to slurry the combined entrained carbon from C1, Cz and C3 streams. On the other hand, the total steam in the C3 fraction would be too great for this purpose. It will be noted that all of the iractions ow from adsorption towers il and 22 at approximately the same pressure.

Referring once more to Figure l, the C3 fraction in line 25 passes into the bottom of the scrubbing zone Sii, which constitutes the lower section of the combined scrubbing and dehumidifying tower 3l. Here the C3 stream, which contains water vapor and entrained activated carbon, is countercurrently contacted with a recirculating watercarbon slurry, whereby the carbon contained in the C3 stream is substantially completely removed. t can be seen that if the slurry formed in scrubbing Zone 3G is continuously recycled by pump 32 through lines 33, Sil, and 35 without any cooling or water addition to the slurry, the temperature of the slurry will gradually reach an equilibrium value corresponding to the adiabatic saturation temperature of the C3 stream. It can further be seen that this condition would create a water deficiency in scrubbing' section S due to the high temperature and sensible heat of the C3 which would vaporize water, with the result that the carbon content or the slurry would soon become too great. This diiculty is used to advantage in the following manner: the C1 and C2 streams in lines El) and 23 respectively are passed to scrubbing zones 36 and 3l respectively. Considering first the C1 stream, the carbon and water Vapor content in this stream are substantially completely and simultaneously removed in zone 36 by countercurrently contacting it with a recirculating carbon-water slurry that is withdrawn from the bottom of zone 38 by pump 38 and passed through lines 39, lill, and Iii and heat exchanger l2 to the top of this zone. The recirculating slurry is cooled suihciently by indirect heat exchange with a coolant in exchanger d2, so as to substantially completely condense all of the water vapor contained in the C1 stream. The carbon-water slurry produced by the operation within tower 36 is usually such that it is too dilute for direct introduction to tower il.

The C2 fraction in line 23 is dehumidied and scrubbed in Zone 3? in a manner similar to that employed for the C1 fraction. The slurry formed in zone 37 is withdrawn by pump 5t and is recirculated through lines 5l and 52 and heat exchanger 43 to the top of this zone. Once again this slurry is cooled suiciently to substantially completely remove all ot the water vapor contained in the C2 stream, as well as to scrub all of the carbon particles from the stream. Again the slurry produced by this operation is too dilute, carbonwise, for direct use in fractionation tower I l. Accordingly, the net product portions of the dilute slurries formed in towers 38 and 3l', over and above that required for the scrubbing and dehumidifying operations, are combined in line 55 and to the recirculating slurry of tower 3| in line in many instances, the water added to the recirculating slurry of tower iii in this manner, less the water vaporised spontaneously in zone 30 of tower 3i, will be within the range of the quantity of water desired to slurry the total carbon recovered from all three feed gases. In these cases, exchanger 5l, the purpose of which is described below, will not be required. It will be noted that the product slurry containing the carbon recovered from all three feed gases is withdrawn through line 55. In the event, however, that the amount of water added via line 55 in the above-described manner is not sufficient to compensate for the water required in the product slurry, the recirculating slurry in line can be cooled in direct heat exchanger 57, so as to control the spontaneous vaporization of water in zone 3d, or even to partially condense a portion of the water vapor contained in the C3 stream, whichever is required. Conversely, where the amount of water added to the recirculating slurry in line 35 via line 55 is greater than that required to compensate for that withdrawn as the product slurry in line 5S, the combined slurries in line 35 can be heated or even boiled in heat exchanger 57, so as to vaporize the excess water which would then combine with the uncondensed water vapor already presentA in zone et, and pass into section 58 of tower 3l where the combined water vapor is condensed in the absence of the carbon fines.

The water vapors or steam flowing into condensation section 58 are condensed by direct contact with previously condensed water that has been collected in tray 5t and recirculated by means of pump G0 through line 6i to the top oi this section. The condensed water, recirculated in this manner, is cooled in indirect heat ex1 changer E3 to an extent such that it will substantially remove all of the water vapor contained in the C3 stream as it passes through section 58. The net water produced in condensation section 56 is withdrawn from the operation through line S2. It will be noted that this water is substantially free of carbon and contaminants such salts and the like, and therefore may be employed for generating steam or other purposes requiring water of this quality. It will further be noted that the C1, C2, and C3 product streams with-drawn through lines lil, 'il and 'i2 are substantially free of both carbon and water vapor.

rThe advantages oi the present process over a process using a separate scrubbing and dehumidifying tower similar to tower 3i for each of several hydrocarbon streams are apparent. In the latter process, each of towers 3 I, 3S, and 3l would contain a solids scrubbing section, a condensation section, two exchangers, two operating pumps, and, according to usual practice, two spare pumps unless the relative capacities of the two operating pumps permits the use of one common spare pump. Thus, the present invention saves a condensation tower section, an exchanger, an operating pump, a spare-pump for the general case, and related auxiliaries such as instruments, 'i r each of all feed gas streams treated except one. For this one feed stream as treated in tower 3l, exchanger 45l is also saved in many cases, as discussed above.

Experimentation has shown that the carbonwater slurry in line l56 usually must contain at least about 0.2 .1b. of -carbon per gallon of slurry and no more than about 0.5 lb. of carbon per gallon of slurry, in order that the slurry will be pumpable and can be directly introduced into fractionation tower l I without impairing the operation of this tower. slurry meeting these requirements is preferably added to adsorptve fractionation tower H at a point within vheating and stripping section Ell. The hot fluidized char in section lf3 will boil the water from the slurry to liberate the carbon and the boiled slurry water will serve as stripping steam. However, excessive slurry water would cool the adsorbent in tower H too much, resulting in impaired desorption and carbon dehydration efficiencies. However, if the slurry is too concentrated, carbonwise, it will not be readily pumpable. To illustrate the mode for operating the process incorporated in the present invention, the handling of C1, C2, and C3 streams having the following characteristics will be considered.

A typical particle size distribution for the activated carbon entrained in the gas streams above is as follows:

Table 3 Entraincd Carbon Composition, wt. percent Particle Size, Microns t will be noted that the Values given in Table f2, while typical, are affected by the type of carbon or adsorbent employed as well as the velocity ci the gases through the adsorption towers.

The C1 stream is contacted with 1550 gallons per minute of reoirculating carbon-water slurry7 in tower 36. A slurry is withdrawn from the bottom of the tower at a temperature of about 180 F. and re-enters the top of the tower at a temperature of about 120 F.

The C2 stream is similarly contacted with 455 G. P. M. of recirculating carbon-water slurry in tower 3l which is withdrawn from the tower at a temperature of 180 F. and recirculated to the top of the tower at a temperature of about 120 F.

47 .5 gallons per minute of slurry from tower 36 and 5 gallons per minute of slurry from tower 3l are combined in line 55. The first named slurry contains about 0.1 lb. `carbon per gallon, while As shown in Figure l, a

.the latter slurry contains about 0.4 lb. carbon per gallon of slurry.

rThe C3 stream is contacted with 1500 gallons per minute of recirculating slurry and with 52.5 gallons per minute (G. P. M.) of lthe combined slurry in line 55 in tower 3|. The slurry withdrawn from the bottom of this tower will have a temperature of about 315 F., while the combined slurry entering the top of the tower will have a temperature of about 314 F. Under these conditions, about 12.5 G. P. M. of water are vaporized spontaneously in zone 30 of tower 3l when exchanger 5l is not used. This leaves 52.5 minus 12.5 or 40 G. P. M. water to slurry the total recovered carbon, which results in a concentration of about 0.5 lb. carbon per gallon of slurry. This concentration is 'allowable for both pumping and for introduction into tower ll via line 55. Thus exchanger 5l is not required.

Q G. P. M. of steam condensate at 240 F. are removed from the bottom of Zone 53 of tower 3l, about 175 G. P. M. of this stream are removed as net product Via line 62, and the remainder is recirculated at 12'O F. via line 5l and exchanger 53 at 120 F. to the top of Zone The Ci, Cz, and C3 streams leave towers 3S, 3l, and 3l respectively at 120 F. and containing small allowable equilibrium quantities of water vapor.

It will be appreciated that the pres-ent invention may also apply to dusty gases in which the condensing Vapor is a hydrocarbon instead of steam, and the recirculated slurries and solidsfree condensate comprises an oil or a hydrocarbon fraction of the feed gases instead ci water. It will be further noted that substantial changes in the operating conditions, number of gas streams, number of towers, etc. can be modiiied or changed without departing from the scope of the invention. In another modiication of the invention, cooling water from a cooling water source, such as a cooling water tower system, may be used in zone 58 of tower 3l for directly condensing water Vapor instead of indirectly via exchanger 63 and recycle condensate in line 5l. ln this modication, exchanger E3 and line 5I, and, in certain cases, pump 60 would be eliminated. The cooling water leaving zone 55 via line 62, containing the Acondensed water vapor, would return to the cooling water system. The condensate would substitute for cooling water makeup usually required in standard cooling water systems. Ordinary cooling water usually contains mineral salts which would contaminate activated carbons. However, the use of direct cooling water in zone 58 is permissible since this water does not contact the carbon.

As another alternate, some of the slurry in line 56 from pump 3'2, or some of the condensate in line 52 from pump $6, may be sent to towers l5 and 31 by means of lines il and 52 respectively. For example, if the solids-to-ccndensible vapor ratio in line 23 is such that the slurry in line 5l is too concentrated in carbon to be readily pumpable, even with the total condensable vapor feed liquied in tower 3l, then the alternate as just described would remedy this condition. it the same time, it may be desirable to increase the cooling at exchanger 5l to provide additional condensate for this purpose. As another alternate, there may be more than one tower of operation and construction similar to tower Si in integrated operation with one or more towers similar in'construction and operation to towers 36 and 3l. Also, a wetting agent, not resulting in permanent damage to the recovered solid, may be added to the scrubbing sections of the various towers to improve the eficienoy of solids removal. These tower scrubbing sections may be equipped with packing, plates, baliles of the disk-and-donut type and other means of staging iines removal and heat exchange between feed gases and recycled slurries.

In still anothei variation or the present process, a single common slurry recycle pump may be used for two or more towers such as towers 36 and 3l instead of a separate pump for each tower, providing the tower pressures and other conditions permit. This procedure would reduce the required number of pumps and tend to correct the condition of slurry water deciency that might occur in one or more towers containing a single contacting section. Such a procedure is illustrated in Figure 2 which depicts another embodiment of the present invention employing a single slurry pump and a common slurry system. It will be noted that the conventional pieces of apparatus shown in Figure l are not shown in Figure 2. It will be further noted, however, that any of the pieces of apparatus in Figure l that are also shown in Figure 2 are designated by the saine characters in both figures.

In discussing Figure 2 it will be assumed that the apparatus shown therein is being employed for the same process and streams as were described in conjunction with Figure l. Thus, the Ci stream of Figure 1 enters scrubbing zone 35 in Figure 2 where its carbon and steam vapor contents are substantially completely and simultaneously removed by contact with a carbonwater slurry that enters the Zone via line du. Similarly, the C2 stream of Figure 1 enters scrubn bing zone 37 of Figure 2 where it is substantially completely and simultaneously freed of its water and carbon constituents by the carbon-water slurry that enters this zone via line 52.

The C3 stream enters the scrubbing zone 3B of tower 3! where the carbon contained in the stream is substantially removed therefrom by contact with a recirculating water-carbon slurry that enters through line 35.

rIhe slurries produced in zones 36, 3l' and Sii are combined in line 8l and pass to pump 32. From pump 32 the combined slurry passes into line 8i with the exception of the product slurry which is withdrawn through line 55.

A first portion of the slurry in line te flows through line d@ and cooler 42 into zone 36 where it scrubs the Ci stream and thereby forms additional slurry. The volume and temperature of the slurry in line si are regulated so as to remove substantially all of the carbon and water vapor contained in the Ci stream.

Similarly, another portion of the slurry in line Si) is cooled in exchanger t3 and passes via line 52 into zone 3l. The temperature and volume of the slurry in line 52 are again controlled so as to scrub substantially all of the water vapor and carbon from the C2 stream.

Finally, another portion of the slurry in line 8B is passed via line 35 and exchanger 5l into zone 36. The volume and temperature of this slurry portion are regulated so that the water content of the combined slurry in line 8i is the amount desired in the product slurry of line 55. As explained earlier in connection with Figure l, it may be necessary in some instances to heat the slurry passing through exchanger 5i' in order to produce a slurry in line 55 of the Water content desired. In other instances it may be neces- 10 sary to cool the slurry passing through exchanger 5l. But, in either event uncondensed water vapor in Zone 30 flows into condensation section 58 Where it is substantially completely condensed.

In reexamining the embodiment of the present invention that is illustrated in Figure 2, it will be observed that this embodiment performs the same functions and realizes the same objectives as the embodiment in Figure l. The embodiment in Figure 2, however, differs from the embodiment in Figure l in that it utilizes merely one slurry pump and a common slurry system for all of the scrubbing zones, etc.

It will be noted that the term activated carbon, as used herein, is intended to include carbons such as activated cocoanut charcoal, bone char, wood char, synthetic coke, and the like.

It will further be noted that for the purposes o' the present invention it is preferred that the non-condensing gases be substantially insoluble in the condensed vapors at the conditions under which the various scrubbing zones are operated.

What is claimed is:

l. A process for removing entrained solid particles and condensable Vapor from a plurality of gasi-form streams each of which also contains a non-condensing gas and wherein one of the streams is relatively rich in condensable vapor and each of the other streams is relatively lean in condensable vapor which comprises in combination scrubbing each of said lean streams in a rst vapor-liquid contacting zone with a iirst portion of a first slurry, each lean stream having its own said rst contacting sone and its own said first slurry, each said first slurry consisting of liquid derived from the condensable vapor contained in its respective said lean stream and of solid particles also derived from its respective said lean stream, each said first portion or" each said first slurry being present in a volume and temperature suicient to remove substantially all of the entrained solid particles and condensable Vapor in its respective lean stream in the form of its respective said rst slurry, cooling and recirculating each said nrst portion of each said. nrst slurry to its respective said i'irst contacting zone, withdrawing and combining the remaining portion oi each said rst slurry with a first portion of a second slurry, contacting the resulting slurry with said gasiform stream relatively rich in condensable vapor in a second vapor-liquid contacting zone, said resulting slurry being present in a volume and temperature sufficient to substantially remove all of the entrained solid particles and a iirst portion of the oondensable vapor contained in said vaporrich stream in the form of said second slurry, recircuiating said iirst portion of said second slurry, withdrawing the remaining portion of said second slurry as a product slurry, said second slurry and each of said first slurries being capable f being pumped and possessing a liquid to solids weight ratio equal to or less than the condens-able vapor to solids weight ratio existing in each slurrys respective gasiform stream, cooling the substantially solids-free rich stream in a third zone to condense out substantially all of the oondensable vapor remaining in this stream, withdrawing the resulting condensate as a product 1iiquid and withdrawing the resulting scrubbed and dehumidied gasiform streams as separate non-condensing gases.

2. A process for fractionating a mixture of C1, C2 and C3 hydrocarbons into separate C1, C2 and C3 streams and for scrubbing and dehumidifying these streams which comprises contacting said mixture with a iiuidized bed of activated carbon in a tower including an adsorption section, a rectication section and a desorption section to form a C1 stream containing steam and entrained carbon particles, a C2 stream containing steam and entrained carbon and a C' stream containing steam and entrained carbon, scrubbing said C1 stream in a first vapor-liquid contacting Zone with a first portion of a rst slurry consisting of water derived from the steam contained in said C1 stream and of carbon also derived from said C1 stream, said iirst portion or" said first slurry being present in a volume and temperature sufiicient to remove substantially all of the entrained carbon and steam from said C1 stream in the form of said first slurry, cooling and recirculating said first portion of said rst slurry to said rst contacting zone and withdrawing the remaining portion of said rst slurry, scrubbing said C2 stream in a second vapor-liquid contacting zone with a rst portion of a second slurry consisting of water derived from the steam contained in said C2 stream and of carbon also derived from said C2 stream, said ilrst portion of said second slurry being present in a volume and temperature suicient to remove substantially all of the entra-ined carbon and steam from said C2 stream in the for-in of said second slurry, cooling and recirculating said first portion of said second slurry to said second contacting zone and withdrawing the remaining portion of said second slurry, combining the remaining portions of said rst and second slurries with a first portion or a third slurry and contacting the resulting slurry with said C3 stream in a third vapor-liquid contacting zone, said resulting slurry being present in a volume and temperature suiicient to substantially remove all of the carbon and a first portion of the steam contained in said C3 stream in the form of said third slurry, recirculating said first portion of said third slurry, withdrawing the remaining portion of said third slurry as a product slurry and pumping said product slurry to said desorption zone, cooling the substantially carbon-free C3 stream in a fourth zone to condense out substantially all of the steam remaining in this stream, withdrawing the resulting water and withdrawing the resulting dehumidied and substantially carbon free C1, C2 and C3 streams as separate C1, Cz and C3 fractions.

3. Process as defined in claim 2 wherein the C1 stream contains about 5 to 39% by volume of steam, the C2 stream contains about 5 to 15% by volume oi steam and the C3 stream contains about 50 to 90% by volume of steam and all three of these streams contain less than about 2 pounds oi' carbon particles per 1000 cu. ft. of gasiform constituents.

4. Process as defined in claim 2 wherein the product slurry contains from about .2 to .5 pound of carbon particles per gallon of slurry.

5. Process as defined in claim 2 wherein the steam condensed in the fourth zone is condensed by contacting the substantially carbon-free Cs stream directly with a portion of the water that has previously been withdrawn from said fourth zone, cooled and recirculated to said fourth zone.

6. A process for removing entrained solid par ticles and condensible vapors from a plurality of gasiform streams wherein the solids are removed in the form of arsingle pumpable slurry product comprised of said solid particles and said condensible vapors in condensed form, each of said gasiform streams containing a non-condensing gas and said solid particles, the total amount of condensible Vapor in the streams being greater relative to the total amount of solid particles than the amount of liquid desired in the slurry product, at least one of said streams being rich in that it contains a relatively low ratio of liquid to solids and at least one of said streams being lean in that it contains a relatively high ratio of liquid to solids which comprises in combination directly scrubbing and cooling each of said rich streams in a first vapor-liquid contacting zone to remove substantially all of the condensible vapors and solid particles in each said rich stream in the form of a rst slurry, each of said rich streams having its own said rst contacting zone and its own said nrst slurry, directly cooling and scrubbing each of said lean streams in a second vapor-liquid contacting zone to remove substantially all of the entrained solid particles therein contained in the form of a second slurry, each said lean stream having its own said second contacting zone and its own said second slurry, passing said first and second slurries to a common slurry system from which portions of said rst and second slurries are passed to said first and second contacting zones to serve as scrubbing media therein, controlling the temperature of said portions passed to each said second contacting zone so as to adjust the ratio oi said condensed vapors to said solid particles at a point within said slurry system at the ratio desired in said slurry product and withdrawing said slurry product at this point, cooling each scrubbed lean stream in its own separate cooling zone to condense substantially all of the condensible vapors remaining therein, withdrawing the resulting condensates formed in said cooling zones, and separately withdrawing-the resulting non-condensing gases substantially free of condensible vapors and solid particles from each oi said rst vapor-liquid contacting zones and each of said cooling zones.

7. Process as defined in claim 6 in which the non-condensing gases are substantially insoluble in the condensed vapors under operating conditions.

8. Process as dened in claim 6 in which at least one of the portions of the rst slurries is cooled and passed to at least one of the iirst vapor-liquid contacting zones.

9. Process as defined in claim 6 wherein substantially all of the condensible vapors remaining in each scrubbed lean stream are condensed by direct contact with previously condensed vapors that have been cooled and recirculated to the cooling zones.

References Cited in the le of this patent Kilpatrick Feb. 12, 1952 

